Claisen allyl ether rearrangement

Claisen Rearrangements - allyl vinyl ether to an y,5-unsaturated carbonyl... 

Claisen rearrangementThe allyl ether 1 when heated rearranges and cyclizes slowly and in low yield to the dihydrobenzofuran 2. However, the dianion (NaH) of 1 rearranges in refluxing DMF mainly to the isomeric dihydrobenzofuran 3, a precursor to the antibiotic ( )-atrovenetin (4). 

The [3, 3] sigmatropic rearrangement of allyl vinyl ethers is known as Claisen rearrangement. Allylic alcohols can be converted to allyl vinyl ethers by mercuric acetate catalysed exchange with ethyl vinyl ether. The allyl vinyl ether need not be isolated because it undergoes rearrangement to 4-pentenal. 

Methods of Preparation qfAllyl Vinyl Ethers 722J The Claisen Rearrangement Allyl Vinyl Ethers... 

Claisen rearrangement. Allyl allenyl ethers resulting from isomerization of allyl propargyl ethers with t-BuOK are ready to undergo Claisen rearrangement. A route to a-substituted acroleins is established. 

You have already seen that a carbon-heteroatom bond is easy to make, since we used such bonds as natural places for disconnections (frames 234 ft). It is good strategy therefore to make a carbon-heteroatom bond and then to transform it into a carbon-earbon bond. The Claisen rearrangement is one way to do this an ortho allyl phenol (B) made from an allyl ether (A) ... 

Conjugate addition of vinyllithium or a vinyl Grignard reagent to enones and subsequent oxidation afford the 1.4-diketone 16[25]. 4-Oxopentanals are synthesized from allylic alcohols by [3,3]sigmatropic rearrangement of their vinyl ethers and subsequent oxidation of the terminal double bond. Dihydrojasmone (18) was synthesized from allyl 2-octenyl ether (17) based on Claisen rearrangement and oxidation[25] (page 26). 

Q The mechanism of the Claisen rearrangement of other allylic ethers of phenol is analogous to that of allyl phenyl ether What is the product of the Claisen rearrangement of C6H50CH2CH CHCH3 /... 

Section 24 13 On being heated allyl aryl ethers undergo a Claisen rearrangement to form o allylphenols A cyclohexadienone formed by a concerted six tt electron reorganization is an intermediate... 

Claisen rearrangement (Section 24 13) Thermal conversion of an allyl phenyl ether to an o allyl phenol The rearrange ment proceeds via a cyclohexadienone intermediate... 

CLAISEN - IRELAND Rearrangment Rearrangement ol allyl phenyl ethers to o (or p-)allylphenols or of allyl vinyl ethers to y.S-unsaturated aldehydes or ketones (Claisen) Rearrangement ol allyl esters as enolale anions to y.S-unsaturated acids (Ireland)... 

This effect is the basis of the synthetic importance of ester enolate Claisen rearrangements in which enolates or silyl enol ethers of allylic esters are rearranged into 4-pentenoate esters. 

Claisen rearrangement of the allyl enol ether of tnfluoroacetylacetone gives a C-allylated derivative [123] (equation 106)... 

Allyl ethers of perfluoroaromatic phenols have been observed to alkylate the aromatic nucleus [106] or to undergo Claisen rearrangement [1071 (equation 54). 

Ether groups in the benzene ring of quinazoline behave as in ethers of homocyclic aromatic compounds, e.g., they can be demethylated with anhydrous aluminum chloride. Allyl ethers also undergo a Claisen rearrangement/ ... 

Thermal [3,3] Claisen rearrangement of the 3-substituted phenyl allyl and pro-pargyl ethers synthesis of 4-halobenzo[d]furans 98H(48)2173. 

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